As the flood of critical biological information swells, medical researchers will drown in it unless it is creatively and effectively organized. Currently, Protein Reviews on the Web (PROW) is a pilot project to use human proteins as the organizing principle around which to build a conceptual web of biological concepts. Its success depends on our developing excellent strategies for organizing information and our tapping into the expertise of the biologic community to help develop and sustain such a resource. The end-product is a WWW resource/journal consisting of online authoritative reviews on human protein (and their orthologs in other species) maintained by biological experts in the research community (http://www.ncbi.nlm.nih.gov/prow). This year the existing body of CD guides has been improved by addition of forum entries from the scientific community, reciprocal links to a central NCBI portal Locus Link, and the introduction of more systematic approaches to family classification. Work on cell surface molecules will continue in conjunction with the upcoming 7th International Workshop on Leukocyte Differentiation Antigens. Moreover, guides have been developed for members of an important, recently discovered family of genes: the killer cell inhibitory receptor (KIR) family. This project is particularly noteworthy because the nomenclature for the family has been chaotic, and this resource provides a expert-initiated nomenclature standardization . In addition to summaries of individual molecules, there is a synthesis of information on the family as a whole (http://www.ncbi.nlm.nih.gov/prow/guide/000001a.htm). Under development is a collection of guides on the intermediate filament superfamily of proteins, including 8 subfamilies and 60 members. The utilization of PROW is growing steadily. It was getting an average of 9,000 hits per month during 1998 but has increased progressively to an average of 15,000 per month during June-August 1999.Of particular importance is the progress we have made in developing the novel KBTool database design and efficient user interface to store and retrieve the complex web of information associated with biological entities and their associated research community. That prototype database currently has grown dramatically to >37,000 objects and >54,000 links. This database is the infrastructure on which PROW is based, enabling biological information to be viewed as an integrated fabric of information. At present some components of the guides are assembled from this database (names, authors, major links, family hierarchy). We are working towards the ability to generate the guides entirely from expert-validated data in KBTool, to allow other views and other useful assemblies of information such as family trees or diagrams of interacting protein networks - database, protein function, proteins,